The theory of lock picking is the theory of exploiting mechanical defects. There are a few basic concepts and de. Anyone can learn how to pick locks.Chapter 1 It's Easy
The big secret of lock picking is that it's easy.

The .nitions but the bulk of the material consists of tricks for opening locks with particular defects or characteristics. The organization of this manual re
ects this structure.

The document ends with a catalog of the mechanical traits and defects found in locks and the techniques used to recognize and exploit them.rst few chapters present the vocabulary and basic information about locks and lock picking. The . There is no way to learn lock picking without practicing. so one chapter presents a set of carefully chosen exercises that will help you learn the skills of lock picking.

Anyone can learn how to open desk and . The exercises are important. The other appendix presents some of the legal issues of lock picking.rst appendix describes how to make lock picking tools. The only way to learn how to recognize and exploit the defects in a lock is to practice. This means practicing many times on the same lock as well as practicing on many dierent locks.

In fact. it is worth pointing out that lock picking is just one way to bypass a lock. though it does cause less damage than brute force techniques. it may be easier to bypass the bolt mechanism than to bypass the lock. but the ability to open most locks in under thirty seconds is a skill that requires practice.ling cabinet locks. usually a better one. It may also be easier to bypass some other part of the door or even avoid the door entirely. Before getting into the details of locks and picking. Remember: There is always another way.
4
.

The terms used to describe locks and lock parts vary from manufacture to manufacture and from city to city. and the vocabulary used in the rest of this booklet.Chapter 2 How a Key Opens a Lock
This chapter presents the basic workings of pin tumbler locks. you should look at . so even if you already understand the basic workings of locks.

The plug is a cylinder which can rotate when the proper key is fully inserted. Wards restrict the set of keys that can be inserted into the plug. Figure 2. The key is inserted into the keyway of the plug. Chapters 3 and 5 present models which will help you understand a lock's response to picking. The protrusions on the side of the keyway are called wards.gure 2. You also need to know how a lock responds to picking. The .1 introduces the vocabulary of real locks. The non-rotating part of the lock is called the hull.1 for the vocabulary. Knowing how a lock works when it is opened by a key is only part of what you need to know.

The proper key lifts each pin pair until the gap between the key pin and the driver pin reaches the sheer line. When all the pins are in this position.rst pin touched by the key is called pin one.
5
. the plug can rotate and the lock can be opened. The remaining pins are numbered increasingly toward the rear of the lock. An incorrect key will leave some of the pins protruding between the hull and the plug. and these pins will prevent the plug from rotating.

1: Workings of pin tumbler locks
6
.Figure 2.

Chapter 3 The Flatland Model
In order to become good at picking locks. The lock is constructed by placing the two plates over each other and drilling holes which pass through both plates. The "
atland" model of a lock is shown in Figure 3. The . This document uses two models to help you understand the behavior of locks. The purpose of this lock is to keep two plates of metal from sliding over each other unless the proper key is present. Chapter 4 uses this model to explain how picking works. This chapter presents a model that highlights interactions between pin positions. you will need a detailed understanding of how locks works and what happens as it is picked.1. Chapter 9 will use this model to explain complicated mechanical defects. It is a cross section of a very simple kind of lock. This is not a cross section of a real lock.

The correct key lifts the pin pairs to align the gap between the pins with the gap between the plates. the key lifts the key pin until its top reaches the lock's sheer line.gure shows a two hole lock. Often the driver and key pins are just called the driver and the pin.3. The bottom pin is called the key pin because it touches the key. the plates cannot slide over each other because the driver pins pass through both plates. The top pin is called the driver pin. If the key is absent. See Figure 3. In this con. A protrusion on the underside of the bottom plate keeps the pins from falling out. and a spring above the top plate pushes down on the driver pin. Two pins are placed in each hole such that the gap between the pins does not line up with the gap between the plates. That is.

3 also illustrates one of the important features of real locks. any parts which slide past each other must be separated by a gap. That is. There is always a sliding allowance.guration. the plates can slide past each other.
7
. The gap between the top and bottom plates allows a range of keys to open the lock. Figure 3.3 is not raised as high as the left pin. yet the lock will still open. Notice that the right key pin in Figure 3.

The . This defect makes it possible to open a lock by lifting the pins one at a time. and thus you don't need a key to lift all the pins at the same time.Chapter 4 Basic Picking & The Binding Defect
The
atland model highlights the basic defect that enables lock picking to work.3 shows how the pins of a lock can be set one at a time. Figure 4.

If the pick is removed. Even though a pin is binding.3c.rst step of the procedure is to apply a sheer force to the lock by pushing on the bottom plate. When the top of the key pin reaches the sheer line. The slight movement of the bottom plate causes a new pin to bind. The same procedure can be used to set the new pin. Figure 4.3b. see Figure 4. the procedure for one pin at a time picking a lock is to apply a sheer force. and the key pin will drop down to its initial position. the driver pin will be held up by the overlapping bottom plate. it can be pushed up with a picking tool. This force causes one or more of the pins to be scissored between the top and bottom plate. Thus. the bottom plate will slide slightly. see Figure 4. The most common defect in a lock is that only one pin will bind. .3a shows the left pin binding.

Push that pin up until you feel it set at the sheer line. Table 4. Find the pin that is binding the most. This is called setting a pin.
1. 3. When the top of the key pin reaches the sheer line. Chapter 9 discusses the dierent defects that cause pins to bind one at a time. 2. and driver pin will be trapped above the sheer line. Apply a sheer force.1: Figure 5: Picking a lock one pin at a time. 4.nd the pin which is binding the most. the moving portion of the lock will give slightly. and push it up. 9
. Go to step 2.

The spring force increases as the pins are pushed into the hull.1. a new contact force arises from the key pin striking the hull. To make a pin move. The pincolumn model highlights the relationship between the torque applied and the amount of force needed to lift each pin. The more torque you apply to the plug. Figure 5. It is essential that you understand this relationship. the spring contact force from above. and the contact force from the key pin below. If the pins are pushed further into the hull. In order to understand the "feel" of lock picking you need to know how the movement of a pin is eect by the torque applied by your torque wrench (tensioner) and the pressure applied by your pick. The binding friction is proportional to how hard the driver pin is being scissored between the plug and the hull. the key pin acquires a binding . See Figure 5. Now the only resistance to motion is the spring force.3. The remainder of this chapter will derive that force graph from the pin-column model. The friction binding force drops to zero and the plug rotates slightly (until some other pin binds). See Figure 5.Chapter 5 The Pin Column Model
The
atland model of locks can explain eects that involve more than one pin. This force can be quite large. which in this case is proportional to the torque. the situation suddenly changes. The pins will not move unless you apply enough pressure to overcome the spring force. but the increase is slight. The amount of pressure you apply to the pick determines the contact force from below. but a dierent model is needed to explain the detailed behavior of a single pin.2 shows a single pin position after torque has been applied to the plug. After the top of the key pin crosses the gap between the plug and the hull. so we will assume that the spring force is constant over the range of displacements we are interested in. When the bottom of the driver pin reaches the sheer line. and it causes a peak in the amount of pressure needed to move a pin. The forces acting of the driver pin are the friction from the sides. the harder it will be to move the pins. you need to apply a pressure that is greater than the sum of the spring and friction forces. A good way to represent this understanding is a graph that shows the minimum pressure needed to move a pin as a function of how far the pin has been displaced from its initial position.

4. See Figure 5. Thus. the amount of pressure needed 11
.ction like the driver pin had in the initial situation.

This analysis is summarized graphically in . the pressure increases dramatically due to the key pin hitting the hull.Figure 5.1: The pin-column model to move the pins before and after the sheer line is about the same. At the sheer line. Increasing the torque increases the required pressure.

gure 5.5.
12
.

2: Binding in the pin-column model
13
.Figure 5.

Figure 5.3: Pins at the sheer line
14
.

4: Key pin enters hull
15
.Figure 5.

Figure 5.5: Pressure required to move pins
16
.

but in the .Chapter 6 Basic Scrubbing
At home you can take your time picking a lock.

5) developed in chapter 5 suggests a fast way to select the correct pin to lift. If the proper torque is being applied. but the driver pin will catch on the edge of the plug and stay above the sheer line. See . the key pin will fall back to its initial position. but it will not enter the hull. As the pick leaves the pin. speed is always essential. The collision force at the sheer line resists the pressure of the pick. Now consider the eect of running the pick over all the pins with a pressure that is great enough to overcome the spring and friction forces but not great enough to overcome the collision force of the key pin hitting the hull. the pin will rise until it hits the hull.eld. This chapter presents a lock picking technique called scrubbing that can quickly open most locks. the plug will rotate slightly. Assume that all the pins could be characterized by the same force diagram.3. so the pick rides over the pin without pressing it into the hull. Any pressure that is above the
at portion of the force graph and below the top of the peak will work. The slow step in basic picking (chapter 4) is locating the pin which is binding the most. The force diagram (Figure 5. As the pick passes over a pin. assume that they all bind at once and that they all encounter the same friction. That is. See Figure 5.

gure 6. You will . Basically. The exercises in chapter 8 will teach you how to choose the correct torque and pressure.1. In theory one stroke of the pick over the pins will cause the lock to open. at most one or two pins will set during a single stroke of the pick. you use the pick to scrub back and forth over the pins while you adjust the amount of torque on the plug. In practice. so several strokes are necessary.

but the primary cause is a misalignment between the center axis of the plug and the axis on which the holes were drilled. Many factors eect this order (see chapter 9).nd that the pins of a lock tend to set in a particular order. See .

gure 6. Scrubbing is fast because you don't need to pay attention to individual pins. If the axis of the pin holes is skewed from the center line of the plug.2. then the pins will set from back to front if the plug is turned one way. and from front to back if the plug is turned the other way. You only need to . Many locks have this defect.

nd the correct torque and pressure. Figure 6. The exercises will teach you how to recognize when a pin is set and how 17
.1 summarizes the steps of picking a lock by scrubbing.

Figure 6.1: Driver pin catches on plug to apply the correct forces.
18
. then it probably has one of the characteristics described in chapter 9 and you will have to concentrate on individual pins. If a lock doesn't open quickly.

2: Alignment of plug holes
19
.Figure 6.

Insert the pick without touching the pins. apply pressure to the pins.1. 4. Gradually increase the torque with each stroke of the pick until pins begin to set. Keeping the torque . 3. Insert the pick and torque wrench. Without applying any torque pull the pick out to get a feel for the stiness of the lock's springs. 2. As you pull the pick out. The pressure should be slightly larger than the minimum necessary to overcome the spring force. Apply a light torque.

increase the torque and scrub the pins with a slightly larger pressure. scrub back and forth over the pins that have not set.1: Figure 13: Basic scrubbing. This will set any pins which have set low due to beveled edges. 5. If additional pins do not set.
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. etc. Once the majority of the pins have been set. Table 6.xed. release the torque and start over with the torque found in the last step.

7. The problem is that the mechanical skills you learned early in life involved maintaining a . advanced lock picking is a craft that requires mechanical sensitivity.Chapter 7 Advanced Lock Picking
Simple lock picking is a trade that anyone can learn. However. physical dexterity. you will grow in many ways.1 Mechanical Skills
Learning how to pull the pick over the pins is surprisingly dicult. If you strive to excel at lock picking. visual concentration and analytic thinking.

xed position or .

you must learn how to apply a . In lock picking.xed path for your hands independent of the amount of force required.

As you pull the pick out of the lock you want to apply a .xed force independent of the position of your hand.

xed pressure on the pins. This is a mechanical skill that can only be learned with practice. The pick should bounce up and down in the keyway according to the resistance oered by each pin. you must train yourself to be sensitive to the sound and feel of the pick passing over the pins. The exercises will help you recognize the important information coming from your . To pick a lock you need feedback about the eects of your manipulations. To get the feedback.

you must train yourself to have a visually reconstructive imagination. Touch and sound provide the most information. For example. but the other senses can reveal critical information. As a beginner.
7. your nose can tell you whether a lock has been lubricated recently. Once you have learned how to build this picture. it is easy to choose manipulations that will open the lock.2 Zen and the Art of Lock Picking
In order to excel at lock picking. you want to project your senses into the lock to receive a full picture of how it is responding to your manipulations. The idea is to use information from all your senses to build a picture of what is happening inside the lock as you pick it.ngers. Basically. All your senses provide information about the lock. you will need to use 21
.

but as you improve you will .your eyes for hand-eye coordination.

nd it unnecessary to look at the lock. it is better to ignore your eyes and use your sight to build an image of the lock based on the information you receive from your . In fact.

Try to ignore the sensations and thoughts that are not related to the lock. Based on an analysis that information the torque is adjusted to make the pins set at the sheer line. picking will go much faster. If you learn to recognize and exploit the "personality traits" of locks. People underestimate the analytic skills involved in lock picking. This will reduce the chances of disturbing the correctly set pins. Varying the torque as the pick moves in and out of the keyway is a general trick that can be used to get around several picking problems. It's the torque wrench that opens the lock. For example. Basically. but as you become better at visualizing the process of picking a lock. Let me propose another way to view the situation. The goal of this mental skill is to acquire a relaxed concentration on the lock. Don't try to focus on the lock. you want to analyze the feedback you get from a lock to diagnose its personality traits and then use your experience to decide on an approach to open the lock. you can increase the torque as the pick moves over the middle pins.
7. then try reducing the torque on the next pass. you will become better at this important skill. They think that the picking tool opens the lock. Don't force the concentration. If some pin doesn't seem to lift up far enough as the pick passes over it. The skill of adjusting the torque while the pick is moving requires careful coordination between your hands. Chapter 9 discusses a large number of common traits and ways to exploit or overcome them. To them the torque wrench is a passive tool that just puts the lock under the desired stress. if the middle pins are set. but the end pins are not. The pick is just running over the pins to get information about the lock.ngers and ears.3 Analytic Thinking
Each lock has its own special characteristics which make picking harder or easier.
22
.

you will get frustrated and your mind will stop learning. The goal of each exercise is to learn something about the particular lock you are holding and something about yourself. If you focus on opening the lock. After about thirty minutes you will . focus on the skills. not on opening the lock. When you do these exercises. while others stress the coordination of skills. If a lock happens to open. Some exercises teach a single skill. These exercises should be practiced in short sessions.Chapter 8 Exercises
This chapter presents a series of exercises that will help you learn the basic skill of lock picking. focus on the memory of what you were doing and what you felt just before it opened.

nd that your .

1 Exercise 1: Bouncing the pick
This exercise helps you learn the skill of applying a .ngers become sore and your mind looses its ability to achieve relaxed concentration.
8.

How you hold the pick makes a dierence on how easy it is to apply a . Basically you want to learn how to let the pick bounce up and down according to the resistance oered by each pin.xed pressure with the pick independent of how the pick moves up and down in the lock.

xed pressure. You want to hold it in such a way that the pressure comes from your .

ngers or your wrist. Your elbow and shoulder do not have the dexterity required to pick locks. While you are scrubbing a lock notice which of your joints are .

The moving joints are providing the pressure. and which are allowed to move.xed. One way to hold a pick is to use two .

ngers to provide a pivot point while another .

nger levers the pick to provide the pressure. Which .

ngers you use is a matter of personal choice. so the pick 23
. If your wrist is providing the pressure. your wrist provides the pressure. A good way to get used to the feel of the pick bouncing up and down in the keyway is to try scrubbing over the pins of an open lock. The pins cannot be pushed down. Do not use your wrist to both move the pick and apply pressure. Another way to hold the pick is like holding a pencil. your shoulder and elbow should provide the force to move the pick in and out of the lock. With this method.

you can hear the rattle. Try to feel the pins rattle as the pick moves over them. then it is false set. This same rattling feel will help you recognize when a pin is set correctly. If a pin appears to be set but it doesn't rattle. False set pins can be . If you move the pick quickly.must adjust to the heights of the pins.

When you are starting.2 Exercise 2: Picking pressure
This exercise will teach you the range of pressures you will need to apply with a pick. just apply pressure when you are drawing the pick out of the lock. Don't think about how you are moving the handle.xed by pushing them down farther. Once you have mastered that. Focus on the tip of the pick. With the
at side of your pick. think about how you are moving the tip of the pick. or by releasing torque and letting them pop back to their initial position. One last word of advice. try applying pressure when the pick is moving inward.
8. push down on the .

rst pin of a lock. apply enough pressure to push each pin all the way down. To help you focus on these sensations. As you draw the pick out of the lock. Notice the sound that the pins make as they spring back. use the
at side of your pick to push down all the pins in the lock. but don't apply any torque. Now see how it feels to push down the other pins as you pull the pick out of the lock. Start out with both the pick and torque wrench in the lock.3 Exercise 3: Picking Torque
This exercise will teach you the range of torque you will need to apply to a lock. Notice the popping feel as a pick goes past each pin. try counting the number of pins in the lock.
8. This force gives you an idea of minimum pressure you will apply with a pick. The spring force increases as you push the pin down. To get an idea of the maximum pressure. perform this exercise to determine the stiness of its springs. See if you can feel this increase. The amount of pressure you are applying should be just enough to overcome the spring force. It demonstrates the interaction between torque and pressure which was describe in chapter 5. padlocks usually have four. If you encounter a new kind of lock. The pins should spring back as the pick goes past them. Door locks at MIT have seven pins. The minimum torque you will use is just enough to overcome the . Sometimes you will need to apply this much pressure to a single pin. Don't apply any torque to the lock. Notice the springy feel as the pick pushes down on each new pin.

Notice how much torque is needed to move the plug before the pins bind.ction of rotating the plug in the hull. This force can be quite high for locks that have been left out in the rain. 24
. The minimum torque for padlocks includes the force of a spring that is attached between the plug and the shackle bolt. Use your torque wrench to rotate the plug until it stops.

To get a feel for the maximum value of torque. you may not be able to hold down more than a few pins. Some of the pins will become harder to push down. If you use too much torque and too much pressure you can get into a situation like the one you just created. use the
at side of the pick to push all the pins down. and try applying enough torque to make the pins stay down after the pick is removed. The key pins are pushed too far into the hull and the torque is sucient to hold them there. Gradually increase the torque until some of the pins set. The range of picking torque can be found by gradually increasing the torque while scrubbing the pins with the pick. If your torque wrench has a twist in it. These pins will loose their springiness. Keeping the torque .

Use this exercise to . The most common mistake of beginners is to use too much torque. use the pick to scrub the pins a few times to see if other pins will set.xed.

Try identifying exactly which pins are set. but it becomes hard to move after that distance (see chapter 6 for an explanation).. You can tell a pin is set because it will have a slight give. When you remove the light pressure.nd the minimum torque required to pick the lock.e. Remember that pin one is the frontmost pin (i. Set pins also rattle if you
ick them with the pick.
8. That is.4 Exercise 4: Identifying Set Pins
While you are picking a lock. the pin can be pushed down a short distance with a light pressure. Try listening for that sound. Run the pick over the pins and try to decide whether the set pins are in the front or back of the lock (or both). the pin springs back up slightly. the pin that a key touches . try to identify which pins are set.

If the front pins set when the plug is turned one way. the back pins will set when the plug is turned the other way.
8. One way to verify how many pins are set is to release the torque. The most important skill of lock picking is the ability to recognize correctly set pins. Try repeating this exercise with the plug turning in the other direction. The picture does not have to be visual. Try to notice the dierence in sound between the snap of a single pin and the snap of two pins at once. You should notice that a larger torque requires a larger pressure to make pins set correctly. Try this. and count the clicks as the pins snap back to their initial position. This exercise will teach you that skill. it could be a rough understanding of which pins are set 25
. Try this exercise with dierent amounts of torque and pressure.rst).2 for an explanation. See Figure 6. A pin that has been false set will also make a snapping sound. the pins will be jammed into the hull and stay there.5 Exercise 5: Projection
As you are doing the exercises try building a picture in your mind of what is going on. If the pressure is too high.

When a lock opens. One way to foster this picture building is to try to remember your sensations and beliefs about a lock just before it opened. don't think "that's over". This exercise requires a lock that you . think "what happened".and how much resistance you are encountering from each pin.

nd easy to pick. It will help you re.

Rehearse in your mind how everything feels when the lock is picked properly. By repeating this exercise.ne the visual skills you need to master lock picking. Pick the lock. Visualize the motion of your muscles as they apply the correct pressure and torque. Now pick the lock again trying to match your actions to the movie. you are learning how to formulate detailed commands for your muscles and how to interpret feedback from your senses. Basically.
26
. The mental rehearsal teaches you how to build a visual understanding of the lock and how to recognize the major steps of picking it. and try to remember how the process felt. you want to create a movie that records the process of picking the lock. and feel the resistance encountered by the pick.

Section 9. the
at edge of the key) away from the nearest doorframe.1 Which Way To Turn
It can be very frustrating to spend a long time picking a lock and then discover that you turned the plug the wrong way. If you turn a plug the wrong way it will rotate freely until it hits a stop. then it probably has one of the traits discussed in this chapter. See Figure 9. If a lock doesn't respond to scrubbing.
9. Cheap padlocks will open if the plug is turned in either direction. The double plug Yale cylinder locks generally open by turning the bottom of the keyway (i. To open the lock. All padlocks made by the Master company can be opened in either direction. When the plug is turned in the correct direction. but here are some general rules.11 also explains how to turn the plug more than 180 degrees if that is necessary to fully retract the bolt.1. Padlocks made by Yale will only open if the plug is turned clockwise. Desk and . The direction to turn the plug depends on the bolt mechanism. Locks built into the doorknob usually open clockwise.Chapter 9 Recognizing and Exploiting Personality Traits
Real locks have a wide range of mechanical features and defects that help and hinder lock picking. The exercises will help you develop the mechanical sensitivity and dexterity necessary to recognize and exploit the dierent traits. you must diagnose the trait and apply the recommended technique.e. Single plug cylinder locks also follow this rule. so you can chose the direction which is best for the torque wrench. you should feel an extra resistance when the plug cam engages the bolt spring. not on the lock.. or until it rotates 180 degrees and the drivers enter the keyway (see section 9.11).

try turning the plug in both directions. so the stop will feel solid. the plug will be stopped by the pins. In the wrong direction the plug will be stopped by a metal tab.
27
. so the stop will feel mushy when you use heavy torque. In the correct direction. When you encounter a new kind of lock mechanism.ling cabinet locks also tend to open clockwise.

1: Direction to turn plug 28
.Figure 9.

2
How Far to Turn
The companion question to which way to turn a lock is how far to turn it. Desk and .9.

See section 9. it is easy to . Locks which are separate from the doorknob tend to require a half turn to open. Turning a lock more than 180 degrees is a dicult because the drivers enter the bottom of the keyway.
9. It should be obvious how to tell the two apart. The nice feature of a lock with the springs at the bottom is that gravity holds the key pins down once they set.11.ling cabinet locks generally open with less than a quarter turn (90 degrees) of the plug. With the set pins out of the way. When opening a desk lock try to avoid having the plug lock in the open position.3 Gravity
Picking a lock that has the springs at the top is dierent than picking one with the springs at the bottom. Deadbolt lock mechanisms can require almost a full turn to open. Locks built into doorknobs also tend to open with less than a quarter turn.

Try a light torque and moderate pressure.4 Pins Not Setting
If you scrub a lock and pins are not setting even when you vary the torque. then the plug cannot rotate enough to allow the other pins to bind. When you encounter this situation. When the springs are on top. Consider a lock whose pins prefer to set from back to front. It is also straight forward to test for the slight give of a correctly set pin. metals behave like springs. or heavy torque and heavy pressure. Set pins also rattle as you draw the pick over them because they are not being pushed down by the driver pin.2). It is hard to recognize that a back pin has false set because the springiness of the front pins makes it hard to sense the small give of a correctly set back pin. gravity will pull the key pins down after the driver pin catches at the sheer line. release the torque and start over by concentrating on the back pins. you can identify the set pins by noticing that the key pin is easy to lift and that it does not feel springy.5 Elastic Deformation
The interesting events of lock picking happen over distances measured in thousandths of an inch.nd and manipulate the remaining unset pins. In this case.
9. The main symptom of this situation is that the other pins will not set unless a very large torque is applied. Very little force is necessary 29
. The click will be easier to feel if you use a sti torque wrench. If the backmost pin false sets high or low (see Figure 9.
9. Over such short distances. then some pin has false set and it is keeping the rest of the pins from setting. Try to feel for the click that happens when a pin reaches the sheer line and the plug rotates slightly.

Deformation can be used to your advantage if you want to force several pins to bind at once. Each pass of the pick will only set the frontmost pin that is binding. the . In particular. With light torque. a single stroke of the pick can set several pins. With the extra torque. Basically.to de
ect a piece metal over those distances.e. the front pin columns bend enough to allow the back of the plug to rotate and thus cause the back pins to bind. Too much torque causes its own problems. If the preference for setting is not very strong (i. This is particularly true if you only apply pressure as the pick is drawn out of the lock. and the lock can be opened quickly. and when the force is removed. the axis of the plug holes is only slightly skewed from the plug's center line). For example. then you can cause additional pins to bind by applying extra torque. but with medium to heavy torque.. the metal will spring back to its original position. the torque puts a twist in the plug that causes the front of the plug to be de
ected further than the back of the plug. the back of the plug stays in its initial position. When the torque is large. Numerous passes are required to set all the pins. the front pins and plug holes can be deformed enough to prevent the pins from setting correctly. picking a lock with pins that prefer to set from front to back is slow because the pins set one at a time.

rst pin tends to false set low.2 shows how excess torque can deform the bottom of the driver pin and prevent the key pin from reaching the sheer line. Figure 9. This situation can be recognized by the lack of give in the .

rst pin. Correctly set pins feel springy if they are pressed down slightly. A falsely set pin lacks this springiness. The solution is to press down hard on the .

You may want to reduce the torque slightly. but if you reduce torque too much then other pins will unset as the .rst pin.

It is also possible to deform the top of the key pin.rst pin is being depressed. The key pin is scissored between the plug and the hull and stays .

the plug will move forward. The problem with a loose plug is that the driver pins tend to set on the back of the plug holes rather than on the sides of the holes. On the outward stroke of the pick. When this happens.
9. the plug will be pushed back. the drivers will unset.xed. If the cam is not properly installed. When you push the plug in. and if you apply pressure on the inward stroke. You can use this defect to your advantage by only applying pressure on the outward or inward stroke of the pick. Alternatively. the pin is said to be false set high.6 Loose Plug
The plug is held into the hull by being wider at the front and by having a cam on the back that is bigger than the hole drilled into the hull. the plug can move in and out of the lock slightly. you can use your .

nger or torque wrench to prevent the plug from moving forward.
30
.

2: Driver pin false set by elastic deformation
31
.Figure 9.

the key pin can enter the hull without colliding with the edge of the hull. If the key pin is small enough and the plug did not rotate very far. As the pins are lifted.7
Pin Diameter
When the pair of pins in a particular column have dierent diameters. This relationship is graphed in the bottom half of the Figure. the plug rotates (until some other pin binds) and the only resistance to motion is the spring force. the pins feel normal at .9. so again the only resistance to motion is the spring force. Basically. the picking pressure is resisted by the binding friction and the spring force. Some other pin is binding.3 shows a pin column with a driver pin that has a larger diameter than the key pin. The top half of Figure 9. that column will react strangely to the pressure of the pick. Once the driver clears the sheer line.

6b shows what happens after the right driver pin sets. The left driver pin in Figure 9. A lock with beveled plug holes requires more scrubbing to open than a lock without beveled holes because the driver pins set on the bevel instead of setting on the top of the plug.
9. It is caught on the bevel. Figure 9. This tends to reduce the wear on the lock and it can both help and hinder lock picking. the bottom plate 32
. This corresponds to the dip in the force graph shown in Figure 5. Yale) bevel the edges of the plug holes and/or round o the ends of the key pins. You can recognize a lock with these features by the large give in set pins. The problem with a large driver pin is that the key pin tends to get stuck in the hull when some other pin sets. and the bottom plate has moved enough to allow the right driver to bind. Once that driver is free. See Figure 9. the key pin will fall back to its initial position while the large driver catches on the edge of the plug hole. The behavior of a large key pin is left as an exercise for the reader.5. The narrow key pin can be pushed all the way into the hull without loosing its springiness.8 Beveled Holes and Rounded pins
Some lock manufacturers (e. the only resistance to motion will be the force of the spring. The bottom plate slides further to the right and now the left driver pin is scissored between the bevel and the top plate. the left driver pin must be pushed up above the bevel. The driver is resting on the bevel.6a is set.4. but then the lock clicks and the pin becomes springy. then the narrow key pin will be in the hull and it will get stuck there when the plug rotates. The plug will not turn if one of the drivers is caught on a bevel. the distance between the height at which the driver pin catches on the edge of the plug hole and the height at which the key pin hits the hull is larger (sometimes as large as a sixteenth of an inch) when the plug holes are beveled or the pins are rounded. There won't be any binding friction. Imagine that a neighboring pin sets and the plug rotates enough to bind the narrow key pin. That is.. If the pick was pressing down on the narrow key pin at the same time as it was pressing down on the pin that set. The key pin must be scrubbed again to push the driver pin up and o the bevel.rst. While the key pin is moving between those two heights. To open the lock.g. but when the picking pressure is released.

3: Driver pin wider than key pin 33
.Figure 9.

If pins unset when you reduce the torque. The most popular shapes are mushroom. The reduced torque will make it easier to push the drivers o the bevels.Figure 9. These drivers stop a picking technique called vibration picking (see section 9. If you encounter a lock with beveled plug holes. The problem with increasing the force is that you may jam some key pins into the hull. see Figure 9. try increasing the torque and the picking pressure.12). If you pick a lock and the plug stops turning after a few degrees and none of the pins 34
.7. The purpose of these shapes is to cause the pins to false set low. and all the pins appear to be set but the lock is not opening. you should reduce torque and continue scrubbing over the pins.9 Mushroom Driver Pins
A general trick that lock makers use to make picking harder is to modify the shape of the driver pin. spool and serrated.4: Beveled plug holes and rounded key pins can slide and the right driver may bind on its bevel.
9. but they only slightly complicate scrubbing and one-pin-at-a-time picking (see chapter 4).

Eventually all the pins will be correctly set at the sheer line. This should put most of the drivers in their cockable position and you can feel for them. even if you lose some of the other pins in the process they will be easier to re-pick than the pins with mushroom drivers. You can identify the positions with mushroom drivers by applying a light torque and pushing up on each pin. and locks that have several spacers for master keying.7. the lip of the driver has caught at the sheer line.ed drivers. Push those pins up to sheer line. See the bottom of Figure 9. This causes the driver to straighten up which in turn causes the plug to unrotate. To pick a lock with modi. Mushroom and spool drivers are often found in Russwin locks. The pins with mushroom drivers will exhibit a tendency to bring the plug back to the fully locked position. One way to identify all the positions with mushroom drivers is to use the
at of your pick to push all the pins up about halfway. By pushing the key pin up you are pushing the
at top of the key pin against the tilted bottom of the mushroom driver. Basically. You can use this motion to identify the columns that have mushroom drivers.

and apply very heavy torque to hold them there. Reducing the torque reduces the binding friction on the pins. use a lighter torque and heavier pressure. In fact.ed drivers. You want to error on the side of pushing the key pins too far into the hull. another way to pick these locks is to use the
at side of your pick to push the pins up all the way. The key to picking locks with modi. Use a scrubbing action to vibrate the key pins while you slowly reduce the torque. The vibration and spring force cause the key pins to slide down to the sheer line.

10 Master Keys
Many applications require keys that open only a single lock and keys that open a group of locks. To allow both the change key and the master key to open the same lock. A mushroom driver set on its lip will not have the springy give of a correctly set driver.8. Usually the change key aligns the top of the spacer with the sheer line. a locksmith adds an extra pin called a spacer to some of the pin columns.
9.ed drivers is recognizing incorrectly set pins. The keys that open a single lock are called change keys and the keys that open multiple locks are called master keys. The eect of the spacer is to create two gaps in the pin column that could be lined up with the sheer line. Practice recognizing the dierence. and the master key aligns the bottom of the spacer with the sheer line (the idea is to prevent people from . See Figure 9.

In general. It is 36
. If the spacer has a smaller diameter than the driver and key pins. In most cases only two or three positions will have spacers. They increase the number of opportunities to set each pin. and they make it more likely that the lock can opened by setting the all the pins at about the same height. You can recognize a position with a spacer by the two clicks you feel when the pin is pushed down. In either case the plug is free to rotate. spacers make a lock easier to pick.ling down a change key to get a master key). then you will feel a wide springy region because the spacer will not bind as it passes through the sheer line.

and serrated driver pins
37
. spool.7: Mushroom.Figure 9.

Thin spacers can cause serious problems. use the
at side of you pick to push the spacer back into 38
.11 for the solution to this problem. If you apply heavy torque and the plug has beveled holes.9 shows how a spacer or driver pin can enter the keyway when the plug is rotated 180 degrees. it will also catch better on the plug.Figure 9. See section 9. you will feel a strong click when the bottom of the spacer clears the sheer line.11 Driver or Spacer Enters Keyway
Figure 9. Since the spacer is larger than the driver pin. You can prevent this by placing the
at side of your pick in the bottom of the keyway before you turn the plug too far. It is also possible for the spacer to fall into the keyway if the plug is rotated 180 degrees. the spacer can twist and jam at the sheer line. If a spacer or driver does enter the keyway and prevent you from turning the plug.8: Spacer pins for master keying more common for the spacer to be larger than the driver pin. If you push the spacer further into the hull.
9. You can recognize this by an increase in friction when the spacer passes through the sheer line.

12 Vibration Picking
Vibration picking works by creating a large gap between the key and driver pins. You may need to use the torque wrench to relieve any sheer force that is binding the spacer or driver. The key pins would transfer their momentum to the driver pins which would
y up into the hull. the plug will rotate when all the 39
. the only option is to remove it. If a spacer falls into the keyway completely. If you are applying a light torque when this happens. A hook shaped piece of spring steel works well for this. the queue ball stops and the other ball heads o with the same speed and direction as the queue ball. Now imagine a device that kicks the tips of all the key pins.
9.Figure 9.9: Spacer or driver can enter keyway the hull. The underlying principle is familiar to anyone who has played pool. If that doesn't work try raking over the drivers with the pointed side of your pick. When the queue ball strikes another ball squarely. though a bent paperclip will work just as well unless the spacer becomes wedged.

You may also need a torque wrench with a narrower head.13 Disk Tumblers
The inexpensive locks found on desks use metal disks instead of pins.
9. The disks have the same outline but dier in the placement of the rectangular cut. Figure 9.
40
.drivers are above the sheer line.1).10 shows the basic workings of these locks. Because the disks are placed close together a half-round pick works better than a half-diamond pick (see Figure A. These locks are easy to pick with the right tools. Use moderate to heavy torque.

10: Workings of a disk tumbler lock
41
.Figure 9.

you must practice and develop a style which . but more importantly it provides you with models and exercises that will help you study locks on your own. not a science. This document presents the knowledge and skills that are essential to lock picking. To excel at lock picking.Chapter 10 Final Remarks
Lock picking is a craft.

Remember that the best technique is the one that works best for you.
42
.ts you personally.

It can also be used to rake over the pins.1 Pick Shapes
Picks come in several shapes and sizes. ease of withdrawal and feel of the interaction. The primary bene. The rake tip is designed for picking pins one by one. The half diamond tip with shallow angles is easy to insert and remove. and in general steep angles give you better feedback about the pins. but the pressure can only be applied as the pick is withdrawn. The shape of the tip determines how easily the pick passes over the pins and what kind of feedback you get from each pin. The design of a tip is a compromise between ease of insertion.
A. Figure A. A tip that has a shallow front angle and a steep back angle works well for Yale locks.13. then it will act like a spring and you will loose the feel of the tip interacting with the pins. See section 9. Unfortunately. The handle and tang of a pick are the same for all picks. The half round tip works well in disk tumbler locks. the steep angles make it harder to move the pick in the lock.1 shows the most common shapes. the pick may not be able to push the middle pin down far enough. If the tang is too thin. It can quickly pick a lock that has little variation in the lengths of the key pins. The full diamond and full round tips are useful for locks that have pins at the top and bottom of the keyway. The handle must be comfortable and the tang must be thin enough to avoid bumping pins unnecessarily. The half diamond pick with steep angles could deal with such a lock.Appendix A Tools
This appendix describes the design and construction of lock picking tools. Some rake tips are
at or dented on the top to makes it easier to align the pick on the pin. The rake tip allows you to carefully feel each pin and apply varying amounts of pressure. so you can apply pressure when the pick is moving in either direction. If the lock requires a key that has a deep cut between two shallow cuts.

t of picking pins one at a time is that you avoid scratching the pins. the multiple bumps 43
. If you want to avoid leaving traces. and it spreads metal dust throughout the lock. you must avoid scrubbing. Scrubbing scratches the tips of the pins and the keyway. The snake tip can be used for scrubbing or picking. When scrubbing.

The snake tip is particularly good at opening .generate more action than a regular pick.

A. Basically.3 describes how to make tools that are less springy. The bristles have the right thickness and width. The resulting tools are springy and strong. by tilting it back and forth. and they are easy to grind into the desired shape.ve pin household locks. You should use moderate to heavy torque with a snake pick to allow several pins to bind at the same time. Section A. and by using either to top or bottom of the tip. When a snake tip is used for picking. The . the snake pick acts like a segment of a key which can be adjusted by lifting and lowering the tip. This style of picking is faster than using a rake and it leaves as little evidence.2 Street cleaner bristles
The spring steel bristles used on street cleaners make excellent tools for lock picking. it can set two or three pins at once.

Course grit sand paper works .rst step in making tools is to sand o any rust on the bristles.

If the edges or tip of the bristle are worn down.ne as does a steel wool cleaning pad (not copper wool). use a .

le to make them square. A torque wrench has a head and a handle as shown in .

The head must be long enough to reach over any protrusions (such as a grip-proof collar) and .gure A.2. The head and the handle are separated by a bend that is about 80 degrees. The head is usually 1/2 to 3/4 of an inch long and the handle varies from 2 to 4 inches long.

The width of the head of a torque wrench determines how well it will . To pick dicult locks you will need to learn how to apply a steady torque via a sti handled torque wrench. it will bump against the doorframe.rmly engage the plug. The handle acts as a spring which sets the torque.g. The handle. The disadvantage of this method of setting the torque is that you get less feedback about the rotation of the plug. The twist makes it easy to control the torque by controlling how far the handle has been de
ected from its rest position. head and bend angle can be made quite small if you want to make tools that are easy to conceal (e. but if it is too long.
ashlight. A long handle allows delicate control over the torque.. or belt buckle). Some torque wrenches have a 90 degree twist in the handle. in a pen.

le the head to the desired width. A general purpose wrench can be made by narrowing the tip (about 1/4 inch) of the head. The tip .

The hard part of making a torque wrench is bending the bristle without cracking it. You will need to twist the bristle more than 90 degrees in order to set a permanent 90 degree twist. Try to keep the axis of the twist lined up with the axis of the bristle. Now move the pliers back another 3/8 inch and apply the remaining 45 degrees. lift the bristle out of the vise by about 1/4 inch (so 44
. clamp the head of the bristle (about one inch) in a vise and use pliers to grasp the bristle about 3/8 of an inch above the vise. You can use another pair of pliers instead of a vise. Apply a 45 degree twist. To make the 80 degree head bend. To make the 90 degree handle twist.ts small keyways while the rest of the head is wide enough to grab a normal keyway.

1: Selection of pick shapes
45
.Figure A.

If you have trouble with this method. A grinding wheel will greatly speed the job of making a pick. Try to keep the axis of the bend perpendicular to the handle.. but it takes less time to practice and make two or three picks than it does to hand . needle nose pliers. Any rounded object will work (e.3/4 inch is still in the vise). This should set a permanent 80 degree bend in the metal. The screwdriver shank ensures that the radius of curvature will not be too small. drill bit. or a pen cap). try grasping the bristle with two pliers separated by about 1/2 inch and bend. Place the shank of a screw driver against the bristle and bend the spring steel around it about 90 degrees. This method produces a gentle curve that won't break the bristle.g. It takes a bit of practice to learn how make smooth cuts with a grinding wheel.

The .le a single pick.

I use two . You can break the bristle by clamping it into a vise and bending it sharply. Otherwise break it o and try again. Hold the bristle at 45 degrees to the wheel and move the bristle side to side as you grind away the metal. you have overheated it. Be sure that the tip of the pick is supported. If the grinding wheel stage is not close enough to the wheel to support the tip. Usually one corner is sharper than the other.rst step is to cut the front angle of the pick. use needle nose pliers to hold the tip. which makes it brittle. The tang should be long enough to allow the tip to pass over the back pin of a seven pin lock. If the tip came out well. and you should grind away the colored portion. cut the back angle of the tip using the corner of the wheel. Cut the tang by making several smooth passes over the corner. and you should use that one. If the metal changes color (to dark blue). Grind slowly to avoid overheating the metal. Hold the pick at the desired angle and slowly push it into the corner of the wheel. The corner of the wheel is also used to grind the tang of the pick. continue. Each pass starts at the tip and moves to the scratch mark. Next. Put a scratch mark to indicate how far back the tang should go. Use the front of the wheel to do this. The side of the stone should cut the back angle. The cut should should pass though about 2/3 of the width of the bristle. Try to remove less than a 1/16th of an inch of metal with each pass.

Use a hand .ngers to hold the bristle on the stage at the proper angle while my other hand pushes the handle of the pick to move the tang along the corner. Use whatever technique works best for you.

le to .

nish the pick. It should feel smooth if you run a .

they will be stronger than tools made from bristles.3 Bicycle spokes
An alternative to making tools out of street cleaner bristles is to make them out of nails and bicycle spokes. you can put some epoxy on the handle before pushing the sheath over it. If the sheath won't stay in place. A strong torque wrench can be constructed from an 8-penny nail (about .1 inch diameter). The outer sheath of phone cable can be used as a handle for the pick. Any roughness will add noise to the feedback you want to get from the lock. slowly remove it from the 46
. First heat up the point with a propane torch until it glows red.
A.nger nail over it. Remove three or four of the wires from a length of cable and push it over the pick. These materials are easily accessible and when they are heat treated.

The burner of a gas stove can be used instead of a torch. Bicycle spokes make excellent picks. Bend one to the shape you want and .Figure A. Temper (harden) the torque wrench by heating to bright orange and dunking it into ice water.2: Torque wrenches
ame. You will wind up with a virtually indestructible bent screwdriver that will last for years under brutal use. Grind it down into the shape of a skinny screwdriver blade and bend it to about 80 degrees. The bend should be less than a right angle because some lock faces are recessed behind a plate (called an escutcheon) and you want the head of the wrench to be able to reach about half an inch into the plug. this softens it. and let it air cool.

Try a right-angle hunk about an inch long for a handle.le the sides of the business end
at such that it's strong in the vertical and
exy in the horizontal direction. . which you need for those really tiny keyways. For smaller picks.

A.4 Brick Strap
For perfectly serviceable key blanks that you can't otherwise . If you're careful you don't have to play any metallurgical games.nd any large-diameter spring and unbend it.

nd at the store. A hand . use the metal strap they wrap around bricks for shipping. you can bend the strap lengthwise by clamping it in a vice and tapping on the protruding part to bend the piece to the required angle. It's wonderfully handy stu for just about anything you want to manufacture. Brick strap is very hard. To get around side wards in the keyway. It can ruin a grinding wheel or key cutting machine.

le is the recommended tool for milling brick strap.
47
.

or to commit any other crime.Appendix B Legal Issues
Contrary to widespread myth. forcing or breaking open a building. use. or begins to make or mend. knowing the same to be adapted and designed for the purpose aforesaid. making. possession. an engine. WITH INTENT TO USE OR EMPLOY OR ALLOW the same to be used or employed for such purpose. machine. room. tool or implement adapted and designed for cutting through. or knowingly has in his possession. IN ORDER TO STEAL THEREFROM money or other property. safe or other depository. vault. or whoever knowingly has in his possession a master key designed to . Burglarious instruments. Whoever makes or mends. it is not a felony to possess lockpicks. Each state has its own laws with respect to such burglarious instruments. Here is the Massachusetts version quoted in entirety from the massachusetts general code: Chapter 266 (crimes against property) Section 49.

shall be punished by imprisonment in the state prison for not more than ten years or by a . TO USE OR EMPLOY THE SAME to steal a motor vehicle or other property therefrom. WITH INTENT.t more than one motor vehicle.

If they stop you for speeding or something. In other words. Emphasis added.ne of not more than one thousand dollars and imprisonment in jail for not more than two and one half years. and . mere possession means nothing.

and does make possession illegal. These are the only other places I have checked. if they catch you picking the lock on a Monec machine they get to draw and quarter you. is Washington. 48
. DC. On the other hand. States with similar wording include ME. I would imagine that most states are similar to Massachusetts. they can't do much. but I would not bet anything substantial (say.nd a pick set. One place that DOES NOT have similar wording. NY. NH. more than a slice of pizza) on it. It may be a good idea to carry around a xeroxed copy of the appropriate page from your state's criminal code.